Logical block addresses (LBAs) are logical locations of data on disk drives. Storing data in accordance with LBA principles is known in the art. Essentially, a LBA describes the location of data, so that the data may be retrieved by looking up its LBA and accessing the location. New data may be overwritten onto old data within an LBA, in which case the LBA may be considered “changed”, in that the data with which the address is associated has changed.
The present invention understands that it is important for certain applications to know when an LBA has changed. For example, knowing which LBAs have not changed since a previous virus check, for instance, can promote more efficient future virus checks by skipping over LBAs that remain unchanged from earlier scans. Or, unchanged LBAs need be checked only for viruses that have been discovered since the last scan. That is, if it is known when an LBA has changed, it is unnecessary to check it against the virus table it was checked against last time, but only against “new” portions of the virus table. Furthermore, if it is known when a LBA was last changed, and if it is also definitively known that a new virus was developed after the change to the LBA, it can be inferred that the new virus cannot have infected the data in the LBA.
As further understood herein, however, a LBA change recordation system ideally is rendered essentially immune from a virus that might be specifically designed to evade it.